CBSE Class 11 Physics Kinematics Assignment

Comprehension
Instantaneous acceleration of particle is defined as rate of change of velocity with time. Slope of graph between v and t gives instantaneous acceleration of the particle.
Five velocity-time graphs (namely I, II, III, IV and V) are shown in the figure.

1. In which case is the acceleration uniform and positive?
(a) I (b) II (c) III (d) IV

2. In which case in the acceleration increasing with time?
(a) I (b) II (c) III (d) IV

3. In which case the acceleration is decreasing with the passage of time?
(a) I (b) II (c) IV (d) V

4. In which case the acceleration is zero?
(a) I (b) II (c) III (d) IV

5. In which case the acceleration is uniform and negative?
(a) I (b) II (c) III (d) IV

Each of the questions given below consists of two statements, an assertion (A) and reason (R).
Select the number corresponding to the appropriate alternative as follows
(a) If both A and R are true and R is the correct explanation of A
(b) If both A and R are true but R is not the correct explanation of A
(c) If A is true but R is false
(d) If A is false but R is true

6. A: Acceleration of body having a uniform circular motion is uniform.
R: Since its magnitude given by V²/R is a constant and its direction is always towards the centre which is again not changing with time

7. A: The v-t graph perpendicular to the time axis is not possible.
R: If v-t graph is perpendicular to the time axis, the acceleration of the particle should be infinite.

8. A. A body can have acceleration even if its velocity is zero at a given instant of time.
R. A body is momentarily at rest when it reverses its direction of motion

9. A. A bullet is fired horizontally from the top of a building and at the same time a stone is just released from the same position. If resistance of air is ignored, then both will hit the ground at the same time.
R. Though bullet travels larger distance, its speed is also large. So ratio of distance travelled and velocity is same in both the cases.

Miscellaneous Assignment
1. (b) 2. (d) 3. (d) 4. (a) 5. (c) 6. (d) 7. (a) 8. (a) 9. (b)